...the only issue is that @pids doesn't seem to be globally referenced...
I'm not sure what you mean by that. This seems to work: 
my ($fh, @pids) = pipeline(
  [qw(ls -1)],
  [qw(sed -e s/t/a/g)],
  [qw(sed -e s/z/b/g)],
  # Let's "hang" for 20 seconds
  [qw(sleep 20)],
);
eval {
  local $SIG{ALRM} = sub { die "alarm\n" };
  # Assume we're "hung" after 5 seconds
  alarm 5;
  while (<$fh>) {
    print "$.:$_";
  }
};
if ($@) {
    die unless $@ eq "alarm\n";
    # Kill the sleep process
    kill 1, $pids[0];
    # timed out
} else {
  close $fh;
}

print "Pids: @pids\n";

[download]
Sorry if I'm misunderstanding, but glad you got it working.

In reply to Re^3: avoiding shell escapes with exec() by runrig
in thread avoiding shell escapes with exec() by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.